Coiled spring



M. sTUBNlTz GOILED SPRING 4April 29, 1930.

Filed June4 22, 1928 3mm/tgz Maurice Stubnitff a@ W5? WQ@ Patented Apr. 29, 1930 UNITED STATES PATENT OFFICE MAURICE STUBNITZ, OF PITTSBURGH. PENNSYLVANIA, ASSIGNOR TO FORT PITT BED- DDIG COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYL- 'VANIA COILED Application tiled June 22,

This invention relates to coiled springs; and it has particular reference to a coiled spring having a helical body portionand a top coil connected to the body portion by one or two turns of less diameter than either the top coil or the turns of the body portion, so pitched as to lie in the same plane as the top coil when the seat is but slightly compressed, these springs being particularly l0 adapted for use in cushion seats; all as more fully hereinafter set forth and as claimed.l

Prior to this invention, it has been customary to make cushion seats by providing a frame including a number of upright helical or coil springs upon which was disposed paddingv and upholstery. One defect of these seats has been the tendency of the padding to fall down within the coils and thus present an irregular, uncomfortable, and unsightly seatinv' surface. To overcome this trouble, it has been proposed to cover the tops of the springs with a netting or wire gauze, or some similar material, to support the padding. This method involves considerable expense, and also detracts from the comfort of the seat. Another proposal has been to position strips of metal or the like across the centers of the springs and along the length of a row of springs. While such strips are cheaper,

.30 like the netting, they detract from the comfort of the seat and are not satisfactory. It is the purposel of the presentinvention to provide means whreby the sagging of the upholstery may be overcome without the cost or discomfort attendant the use of vlietting or strips as is the case with prior art constructions.

Other principles of the invention and the advantages to be derived fromA a. practice thereof will appear from the following detailed description, read in connection with the accompanying drawing, wherein:

Fig. 1 is a fragmentary crossfsectional view of a cushion seat including the springs of the present invention; and I Fig. 2 is a perspective view of a spring made in accordance with the present inventin. i I

The assembly shown in Fig. 1 comprises a rectangular lower border frame 10 between SPRING 192s. serial No. 287,601.

opposite sides of which are mounted a number of cross-bars 11 upon which are disposed springs 12, which are interconnected at their upper ends by means of clips 13. At the top of the springs 12 is disposed suitable padding 11 which is encased by an envelope or fabric 15 drawn down around the sides of the frame and secured under the border frame 10 by means of a U-shaped metallic clamp 16. In one way of assembling the seat shown in Fig. 1, the fabric 15 is spread out on a flat surface, and the padding 14 is laid on the fabric. The border frame 10, cross-bars 11, and springs 12, previously assembled, are then disposed in an upside down position on the padding 14, and slightly compressed. Then the fabric 15 is drawn under the border frame 10 and is secured, while the springs are under slight compression, by means of the clamps 16.

It will be observed that no provision is made for the inclusion of netting or long strips over the tops of the springs. The short clips 13' simply join adjacent edges of the springs 12, but-do not pass across their tops. Such means as netting or strips are not required to prevent sagging, as the springs themselves are so constructed as to obviate the necessity for them.

A typical spring is shown in Fig. 2. This spring consists of a continuous coil of wire tempered to impart resiliency, and having a base coil 20, body coils 21, and top coil 22. While the drawing shows springs of the con' ical type, it will be understood that the usual types of prior art spring shapes may also be employed. For example, the body portion 21 may be conical or cylindrical, the bottom coil 20 may be of greater or less diameter than the body coils, and the top coil 22, while usually of greater diameter than the body coils 21, nevertheless need not be so dimensioned. The bod coils 21 are so wound that each turn has a e inclination to the horizontal, that is, the turns of the body portion are substantially lof uniform pitch, due regard being had to manufacturing tolerances. As thus far described, the spring involvesl nothing new over prior art practice, and is theof 1' sprmg with which means need be employed y101l to prevent sagging of the upholstery. The spring illustrated, however, also includes one or two turns 24, interposed between and connecting the top coil 22 and the body coils 21, which turns 24 are of materially less diameter than the adjacent body or top turns, and which are also, (if there be more than one) tightly wound, and wound with a less'pitch or inclination to the horizontal than the turns -of the body of the coil.

Such springs may be used without netting or supporting strips, and not only are more satisfactory from the viewpoint of comfort and utility, but a-lsoentail considerable economies in manufacture. Thus, as shown in a somewhat exaggerated way' in Fig. 1, in use, the padding 14, falling within the top coil 22, is caught by the turns 24 and supported by them. In this Way the sagging heretofore exerienced is overcome. Another` feat-ure owing from the use of these coils, with the concurrent omission of the prior art supporting means, is that each coil possesses a greater 'flexibility than is the case when the movement of the springs is restrained by netting or strips. A cushion seat should press uniformly over each point of the load imposed thereon, irrespective of irregularities in the surface of the load applied. This effect could perhaps perfectly accomplished by providing a myriad of independant springs, a condition which is of course limited to an approximation by obvious factors. The inclusion of a netting, or strips connecting a number of coils, of course detracts from the individuality of spring action, and so recties sagging at the expense of comfort. In thepresent invention, the individuality of the spring action is retained, and the sagging eii'ect is also overcome.

In some cases, particularly when assembling l the seat by the compression method described briefly above, it is advantageous to space the little connecting coils 24 from the top coils 22 so that, during assembly, the top coil and the little coils lie in substantially the same plane. That is, the top coil and connecting little coil telescope, but, ydueto the relative softness of the top coil, the turns of the body portion do not telescope. In this method of assembling, the padding is initially rendered smooth on its lnner, as well as its outerv surface, thereby enhancing the smoothness and longevity of the entire upholstery. Other featuresl of the 4invention will become apparent to those skilled in the art without further description, to whom it will also be apparent that I intend the invention to be limlted by the scope of the following claims, and nxfit to a single illustrative embodiment thereo 1. A helical spring comprising a body portion, atop end coil of greater diameter than the body portion, and a spacing ringof less diameter than either the top end coil or the body portion, said top end coil and spacing ring lying in parallel planes at right angles to the longitudinal axis of the spring, said spacing ring directly connected to said top end coil and said body portion by arcs of helical spirals in a manner to cause said top end coil and said spacing ring to compress and lie in the same plane upon `application of light loa-ds along the longitudinal axis of the spring without substantially compressing vspacing coil being less resiliently connected to said body portion than to said top end coil.

In testimony whereof, I have hereunto affixed my signature. y MAURICE STUBNITZ iso 

